1. Field of the Invention
The present invention relates to a pipe heater encircled conduit device in which the heat energy can be transferred through a space between a hollow inner quartz tube and a hollow outer quartz tube by both actions of heat conduction and radiation.
2. Brief Description of the Prior Art
As shown in FIG. 10, conventional pipe heater (3) generally has a hollow metal pipe (31) in which a heating element (32) is provided, and electrode pins (33) for connection with outside power source are connected to both ends of the heating element (32). Kaolinite (34) for insulation purpose is filled within the hollow metal pipe (31). Then, the hollow metal pipe (31) is rolled so as to make the filled kaolinite become more compact. Both ends of the hollow metal pipe (31) are sealed by the resin glue (35) so that the interior of the hollow metal pipe (31) is in sealed state. However, the pipe heater (3) is placed within the barrel having heat insulation that is used to hold water. The hollow metal pipe (31) in long term contact with water causes oxidization easily which results in gradual corrosion. Serious corrosion often leads to the rupture of the hollow metal pipe (31), in turn gives rise to current leakage problem. Furthermore, large amount of mineral materials contained in the water also cause impurities or scale formation on the pipe. The scale formation on the pipe will bring about resistance to the transfer of the heat generated from the pipe heater (3), i.e, deterioration of heat transfer efficiency.